In 2000, scientists drilled a hole into the Siberian permafrost to collect old soil and look for ancient predators. In fact, these soil samples were estimated to be around 30,000 years old. These viral predators may be even older. Ten years later, the researchers added portions of these samples to amoebae colonies to see if any of the viruses from the soil would infect the amoebae. They were basically “fishing” by using amoebae as bait. The scientists found a virus new to science and named it Pithovirus sibericum. It was giant, measuring about 1.5 micrometers long. After 30,000 years, P. sibericum had been thawed and brought back to life.
Viruses are a large part of the planet’s biomass. Bacteriophages, or phages, are specific viruses that infect bacteria. Phages are the most abundant organism on Earth, with an estimated number of ten million trillion trillion (10^31). If phages were the size of an average beetle, they would completely cover the entire surface of the Earth several miles deep. They are abundant, but we know so little. Groups of student researchers are exploring this unknown realm.
This past semester, scientists at Mitchell Community College collected soil samples from Iredell County, then extracted, purified, and amplified new phages. The research was done in partnership with Howard Hughes Medical Center’s SEA-PHAGES program. SEA-PHAGES is seeking to find, characterize, and sequence phages that infect bacteria from the Actinobacterial family. The goal is to better understand the diversity within and between these phages. Instead of amoebae, Mitchell researchers used a bacteria, Microbacterium foliorum, as bait to catch the viruses.
Mitchell scientists discovered seven new viruses (seen here), and chose two phages for DNA sequencing. Next semester, the students will learn more about these phages by exploring their genome. The diversity of phages that inhabit Iredell County soil will become a little less blurry.